I just wanted to show off tbh (it's not that difficult though honestly, just gotta be lucky with Ravager spawns for some classes). Here's my tier list of each class (that I currently own) playing mob arena solo in its current state (tbh it's almost based entirely off how well these classes can survive against Ravagers). S tier: The cream of the crop, the bestest and most fun classes to currently play on mob arena, both by yourself or with others. A tier: Let's be honest, any class with a shield is an A tier class, so I've placed Knight and Titan here. B tier: Range is another way to kill those normally-hard-to-melee mobs, and the archer does that pretty well. It gets B tier all to itself. C tier: C stands for Can kill Ravagers, and these classes can do just that! (although badly) D tier: These are classes that essentially cannot survive if a Ravager spawns in any wave (and honestly, it's difficult surviving other waves with these classes solo as well), but they're better than enchanter (and I want to fill out the tier list with at least one class in each tier). F tier: I do not recommend playing this class alone unless you want a challenge.
Here's a couple of tips for mob arena that I've learned while playing (although I doubt anyone who doesn't already know these will read this): Thank you for coming to my TED Talk.